Wave overtopping and crown wall stability of cube and Cubipod-armored mound breakwaters
[EN] The influence of the type of armor on wave overtopping on mound breakwaters is usually represented by the roughness factor. However, different values of roughness factor for the same armor unit are given in the literature. Thus, the roughness factor depends not only on the type of armor, number...
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| Tipo de recurso: | tesis doctoral |
| Fecha de publicación: | 2016 |
| País: | España |
| Institución: | Universitat Politècnica de València (UPV) |
| Repositorio: | RiuNet. Repositorio Institucional de la Universitat Politécnica de Valéncia |
| Idioma: | inglés |
| OAI Identifier: | oai:riunet.upv.es:10251/62178 |
| Acceso en línea: | https://riunet.upv.es/handle/10251/62178 |
| Access Level: | acceso abierto |
| Palabra clave: | Wave overtopping Crown wall Roughness factor Cubipod, mound breakwater INGENIERIA E INFRAESTRUCTURA DE LOS TRANSPORTES |
| Sumario: | [EN] The influence of the type of armor on wave overtopping on mound breakwaters is usually represented by the roughness factor. However, different values of roughness factor for the same armor unit are given in the literature. Thus, the roughness factor depends not only on the type of armor, number of layers and permeability but also on the formula and database considered. In the present thesis, a new methodology based on bootstrapping techniques is developed and applied to characterize the roughness factors for different armor units. Differences up to 20% appeared when comparing the optimum roughness factors with those given in the literature. Armor porosity greatly affects the roughness factor and the armor stability: higher armor porosities reduce wave overtopping as well as hydraulic stability. Therefore, armor porosity values usually recommended in the literature should be used to avoid damage during lifetime. Formulas with few variables are easy to apply but they allow the roughness factor to absorb the information not explicitly included in the formula. However, the CLASH neural network avoids this problem and gives excellent estimation for wave overtopping on mound breakwaters. In this thesis, a new formula which emulates the behavior of the CLASH neural network is developed. The new formula has 16 parameters, six dimensionless input variables (Rc/Hm0, Ir, Rc/h, Gc/Hm0, Ac/Rc and a toe berm variable based on Rc/h) and two reduction factors (¿f and ¿ß). The new formula is built-up after systematic simulations using the CLASH neural network and provides the lowest prediction error. Wave overtopping on mound breakwaters can be minimized by increasing the crest freeboard, usually with a concrete crown wall. Crown walls must resist wave loads and armor earth pressure to be stable. In the present study, small-scale test results with cube- and Cubipod-armored mound breakwaters are used to develop a new estimator for calculating horizontal and up-lift forces from waves. The new formulas include four dimensionless input variables (¿f Ru0.1%/Rc, (Rc-Ac)/Ch, ¿(L_m/G_c ) and Fc/Ch) and the crown wall geometry. The roughness factor selected for overtopping prediction is used to consider the type of armor. Up-lift forces decreased sharply with increasing foundation levels. The new formulas provide the lowest error when predicting wave forces on crown walls. |
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